The $2.99 laser trigger

(laser not included!) Its actually an IR trigger, but lasers are so much cooler! I wanted to trigger the camera to very specific action so I thought i'd get an optical trigger. There are a few commercial ones out there but as a fun hobby project (I love repurposing equpment btw) I thought this toy RC car lap timer would make for good inexpensive optical trigger. After adding a plugin jack and a diode, I had one that will trigger my pocket wizard which in turn will trigger my D300.

The lap timer is actually made for the Radio Shack ZipZap mini rc cars. They can be found for just $2.99 shipped on ebay. I comes with the lap timing scoreboard and an IR beam railing for the opposite side of the lane. two AA's power the lap timer, and 2 AAA's power the IR emitter bar. You can use the emmiter bar to make a beam for triggering. It works well but the object needs to be big enough to completely block its wide range. The laser level I'm using on the otherhand has a very tight beam, and even a single water drop passing through its path can trigger it.

While testing the stock unmodified lap timer I noticed that the Red LED on top would turn off whenever the beam was broken and be on when the IR beam was seen by the timer. So I decided to do a quick modification by adding a diode and an 1/8" (3.5mm) mono connector. That would allow it to connect to a pocket wizard transmitter.

The transmitter would trigger my DSLR with the addition of an inexpensive pre-trigger cord from Calumet (it was $9.99)

For the Canon folks...

Here it is in action, this is reject test shot that happens to show everything. You can see the laser on the right side, my water dropper in the middle, and the laser trigger on the left. The drop broke the beam, and traveled the distance seen when the camera shot it. For those needing a poor mans adjustable delay and using flash (in a dark room), one trick you can do is rear curtain sync. By syncing rear curtain you can adjust when the flash goes off, and in turn creates your exposure. If you need more discrete timing you'll have to build an adjustable delay (I've done that too, but thats another blog..)

A prettier example of it in action. using this method I can get pretty repeatable drops in front of my camera. Not the most exciting use of this trigger, but it shows it works and is repeatable.

Here is another example of the trigger, I had another photographer "spray" the camera with a card ala 52 card pickup. The laser trigger was in front of him, and I prefocused the camera so that when the cards did break the beam they would be in focus. We did a this a few times and got pretty good results, I plan on doing some more exciting triggering once things warm up and I can get outside.

All in all the trigger has been a success, it looks a little funny, but hey it cost less then a happy meal and now I can trigger things like the cool sharks in Austin Powers!